Test probe



Feb. 6, 1945. M. PITINSKY ETAL 2,368,678

TEST PROBE Filed Nov. 1'7, 1943 INVENTOR. H.M.QERST,MA.SHRIRO 8-. MPITINSKY flfarney Patented Feb. 6, 1945 TEST PROBE.

Mon-is Pitinsky and Henry M. Gerst, Eatontown,

and Morris A. Shriro, Elberon, N. J. I 1

Application November 17,1943, Serial No. 3: Claims. (01. 173-324 (Granted under the act of March 3, 188 3, as

amended April 30, 1928; 370 0. G; 757) This invention relates to a testing device, and

particularly ,toa probe which is used in connec tion with means. for making electrical andradio measurements in confined space.

According to conventional practice, probes used in'connectidnWith electrical and radio measurements are so constructed that measurements are difiicult of attainment in restricted space. With the advent of miniature tubes and the attendant reduction in size or radio units the compactness of same made necessary the design of a probe which could be used'in making electrical or radio measurements Without the danger of causing electrical short. circuits, damaging, or disturbing the components under test.

The object of the present invention therefor, is to provide an improved test probe, the construction of which permits the reduction of electrical short circuits to a minimum when testing radio or electronic equipment.

A further object in the construction of this invention is to make possible tests of equipment in restricted space.

' parts'is rapidly accomplished in overcome any ing out of shape.

In theevent oraa age to the invention, seeis so constructed. that replacement, of any of thef will be described furtheralong.

' For a better understanding of the' invention? together with other and furtherobiectsithereof,

reference is made t o the followingdescription taken t-ogetherwith the following drawing-and its scope. a 1

1 p n n d a n jfl l st t the' vention in cross section and is,desighatedas' urel. j f

Referring now particularly to the drawingj'the invention comprises a single-conductor cane 213% A still further object is to provide a probe capable of making tests of equipment using miniature radio tubes.

In the design of this invention, particular consideraticn was given to the following conditions.

The probe point of a test probe must be shaped to permit ingress to the orifices in miniature tube sockets now in general use in compact electronic or radio equipment.

The sockets of the aforementioned miniature tubes are so constructed that the contacts are recessed in the orifices of the tube socket a predetermined distance below the surface of same. The orifices of the miniature tube sockets are small in diameter as is well known to those versed in the art, and access to the contacts in the orifices is diflicult when using the conventional test probe.

In addition to the aforementioned difliculty encountered in testing electronic or radio equipment using miniature tubes is the compactness of the equipment itself. In such restricted space, the use of conventional probes make tests and measurements difficult.

The invention overcomes this particular obstacle by providing a probe point of sufficient length and small diameter, properly insulated toobviate short circuits, and flexible enough to a conductor 2B,"terminati'ng iri' a commereai plug 22, a non-ferrous cylinder 24 threaded externally along its 'entire length, a handle 21 of dielectric substance threaded internally e, predetermined distance, a removable section 28 of said handle 21, an insulating cover 25 and a probe point 23 of predetermined length composed of hardened but resilient wire and being arcuated a predetermined distance from the end thereof.

In the assembly of this invention the cable 2| is inserted in the commercial plug 22 and attached to same by means that are known to those versed in the art. The handle 21 is' now slipped over the cable 2| before proceeding with the next step to be described herein.

The conductor 26 of cable 2| is inserted in a recess of predetermined depth along the longitudinal axis of the non-ferrous cylinder 24. Conductor 26 is attached to the said cylinder 24 by soldering same to the said recess of cylinder 24.

The handle 21 may now be screwed on to the cylinder 24 a predetermined distance along the length of said cylinder.

The probe point 23 is wedged into a recess of predetermined distance along the longitudinal axis of cylinder 24 and in juxtaposition to conductor 26. An insulating sleeve 25 is slipped over the probe point 23 and covers the entire probe tip 23 with the exception of a predetermined distance from the arcuated and tapered: end of saidtendency"toward'breaking stee -e;-

w l be m with theepp jnd df screwing sections'll and 28 which comprise the {handle and thusfexposing the cylinder 24 and making possible the replacement of the probe point 23 by unsoldering the conductor 26 from Y the cylinder 24fand replacing same with an assembly comprising probe 23, insulating sleeve 25 and cylinder 24;";The assembly comprising 23,

- 24 and 25 may be assembled beforehand and kept of miniature tube sockets in a manner Well known to those skilled in the art without damage to this component. j I While there has been described what is at present considered the preferred embodiment of the invention, it'will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is, therefore, aimed in the, appended claiins to cover all such changes and modifications as fall within the true spirit and scope of the invention. I

i Whatis claimed is: 1. A test probe includinga probe rod the outer end of said rod having a pointand a curved poran interconnecting plug of said rod, a conducsaid plug electrically tion adjacent said point, connected to the inner end tor connected to'said plug,

interconnecting said rod and said conductor, said conductor being adapted for connecting said probe to an instrument panel, a hollow insulatinghandle surrounding said conductor and fitting over one end of said plug, and an insulating bush plug interconnecting said conductor and said rod, and a hollow handle fittingover said plug, said handle being circumferentially split intermediate its ends and adapted, when separated at said split, to expose said plug and to make it accessible for replacing said rod in case of damage.

3. A test probe comprising, a conductor suitable for connecting the probe to an instrument, a metallic test rod having a point adapted for contact with an element of the circuit to be tested, a metallic cylinder joiningsaid conductor and said rod and having a screw thread on its annuw lar surface, a'tube of insulation having a screw thread on its inner surface interfitting with the screw, thread on said cylinder, and a second tube of insulation having. screw thread on it inner surface interfitting With the screw thread on said cylinder saidtubes extending beyond the ends of said cylinder and providing a handle and affording a locking arrangement by interengagement with each other atan end of each tube and furnishing delicate adjustment of the distance between the end of said rod and the end of the adjacenttube. r I r V MORRIS PITINSKY.

HENRY M. GERST. M. A. SHRIRO. 

